add log level prefix color

os/glog/glog_logger.go

@@ -43,6 +43,7 @@ const (
 	defaultFilePerm   = os.FileMode(0666)
 	defaultFileExpire = time.Minute
 	pathFilterKey     = "/os/glog/glog"
+	bufferStdOut	  = "stdOut"
 )
 
 const (
@@ -220,20 +221,19 @@ func (l *Logger) print(ctx context.Context, level int, values ...interface{}) {
 
 // printToWriter writes buffer to writer.
 func (l *Logger) printToWriter(ctx context.Context, input *HandlerInput) {
-	buffer := input.Buffer()
 	if l.config.Writer == nil {
 		// Output content to disk file.
 		if l.config.Path != "" {
-			l.printToFile(input.Time, buffer)
+			l.printToFile(input.Time, input.Buffer())
 		}
 		// Allow output to stdout?
 		if l.config.StdoutPrint {
-			if _, err := os.Stdout.Write(buffer.Bytes()); err != nil {
+			if _, err := os.Stdout.Write(input.Buffer(bufferStdOut).Bytes()); err != nil {
 				intlog.Error(err)
 			}
 		}
 	} else {
-		if _, err := l.config.Writer.Write(buffer.Bytes()); err != nil {
+		if _, err := l.config.Writer.Write(input.Buffer().Bytes()); err != nil {
 			// panic(err)
 			intlog.Error(err)
 		}

os/glog/glog_logger_chaining.go

@@ -245,3 +245,14 @@ func (l *Logger) Async(enabled ...bool) *Logger {
 	}
 	return logger
 }
+
+func (l *Logger) Color(color logColor) *Logger {
+	logger := (*Logger)(nil)
+	if l.parent == nil {
+		logger = l.Clone()
+	} else {
+		logger = l
+	}
+	logger.SetColor(color)
+	return logger
+}

os/glog/glog_logger_config.go

@@ -42,6 +42,7 @@ type Config struct {
 	RotateBackupExpire   time.Duration  `json:"rotateBackupExpire"`   // Max expire for rotated files, which is 0 in default, means no expiration.
 	RotateBackupCompress int            `json:"rotateBackupCompress"` // Compress level for rotated files using gzip algorithm. It's 0 in default, means no compression.
 	RotateCheckInterval  time.Duration  `json:"rotateCheckInterval"`  // Asynchronizely checks the backups and expiration at intervals. It's 1 hour in default.
+	color                logColor       `json:"-"`
 }
 
 // DefaultConfig returns the default configuration for logger.
@@ -252,3 +253,7 @@ func (l *Logger) SetPrefix(prefix string) {
 func (l *Logger) SetHandlers(handlers ...Handler) {
 	l.config.Handlers = append(handlers, defaultHandler)
 }
+
+func (l *Logger) SetColor(color logColor) {
+	l.config.color = color
+}

os/glog/glog_logger_handler.go

@@ -9,6 +9,7 @@ package glog
 import (
 	"bytes"
 	"context"
+	"fmt"
 	"time"
 )
 
@@ -42,11 +43,15 @@ func (i *HandlerInput) addStringToBuffer(buffer *bytes.Buffer, s string) {
 	buffer.WriteString(s)
 }
 
-func (i *HandlerInput) Buffer() *bytes.Buffer {
+func (i *HandlerInput) Buffer(bufferType ...string) *bytes.Buffer {
 	buffer := bytes.NewBuffer(nil)
 	buffer.WriteString(i.TimeFormat)
 	if i.LevelFormat != "" {
-		i.addStringToBuffer(buffer, i.LevelFormat)
+		if len(bufferType) > 0 && bufferType[0] == bufferStdOut {
+			i.addStringToBuffer(buffer, i.getLevelFormatWithColor())
+		} else {
+			i.addStringToBuffer(buffer, i.LevelFormat)
+		}
 	}
 	if i.CallerFunc != "" {
 		i.addStringToBuffer(buffer, i.CallerFunc)
@@ -67,6 +72,16 @@ func (i *HandlerInput) Buffer() *bytes.Buffer {
 	return buffer
 }
 
+// getLevelFormatWithColor returns the prefix string with color.
+func (i *HandlerInput) getLevelFormatWithColor() string {
+	s := i.LevelFormat
+	color := defaultLevelColor[i.Level]
+	if i.logger.config.color != 0 {
+		color = i.logger.config.color
+	}
+	return fmt.Sprintf("\x1b[0;%dm%s\x1b[0m", color, s)
+}
+
 func (i *HandlerInput) String() string {
 	return i.Buffer().String()
 }

os/glog/glog_logger_level.go

@@ -29,6 +29,19 @@ const (
 	LEVEL_FATA             // 1024
 )
 
+type logColor int
+
+const (
+	COLOR_BLACK logColor = 30 + iota
+	COLOR_RED
+	COLOR_GREEN
+	COLOR_YELLOW
+	COLOR_BLUE
+	COLOR_MAGENTA
+	COLOR_CYAN
+	COLOR_WHITE
+)
+
 // defaultLevelPrefixes defines the default level and its mapping prefix string.
 var defaultLevelPrefixes = map[int]string{
 	LEVEL_DEBU: "DEBU",
@@ -41,6 +54,18 @@ var defaultLevelPrefixes = map[int]string{
 	LEVEL_FATA: "FATA",
 }
 
+// defaultLevelColor defines the default level and its mapping prefix string.
+var defaultLevelColor = map[int]logColor{
+	LEVEL_DEBU: COLOR_YELLOW,
+	LEVEL_INFO: COLOR_GREEN,
+	LEVEL_NOTI: COLOR_CYAN,
+	LEVEL_WARN: COLOR_YELLOW,
+	LEVEL_ERRO: COLOR_RED,
+	LEVEL_CRIT: COLOR_RED,
+	LEVEL_PANI: COLOR_RED,
+	LEVEL_FATA: COLOR_RED,
+}
+
 // levelStringMap defines level string name to its level mapping.
 var levelStringMap = map[string]int{
 	"ALL":      LEVEL_DEBU | LEVEL_INFO | LEVEL_NOTI | LEVEL_WARN | LEVEL_ERRO | LEVEL_CRIT,